This invention relates to buildings, building components, building subassemblies, and building assemblies, and to methods of constructing buildings. This invention relates specifically to components, subassemblies, and assemblies, as parts of the building, and to the issue of worker safety during the construction of buildings.
From time to time, injuries occur during construction of buildings, including to workers who fall from elevated heights. The focus of this invention is to provide novel methods of installing fall protection systems in buildings being constructed, thereby to assist building contractors in reducing, desirably eliminating, the number of incidents of worker injuries resulting from workers falling from elevated heights while working on construction of such building.
Governmental safety organizations, for example the Occupational Safety and Health Administration (OSHA) in the US, have promulgated required safety standards, and safety practices to generally provide safety systems which capture and support workers who are working at substantial heights above supporting surfaces, to protect such workers, namely to stop a fall, and to support such workers if/when such workers do fall. But it is up to the industry to create fall protection systems which meet the required standards.
Pre-engineered metal building systems are the predominant method of non-residential low rise construction for buildings. Existing fall protection standards have substantial impact on the contractors involved in such pre-engineered metal building systems.
One way a worker can be protected, according to the standards, is for the worker to wear a safety harness which is tied, by a strap, to the building structure at elevation such that the harness/strap combination stops any fall which the worker experiences before the worker encounters an underlying surface such as a floor or the ground. Use of such safety harness is known as “tying off”. But tying the harness to the building limits the worker's mobility, as well as the worker's range of movement. Thus, tie-off harnesses are not viewed favorably in the industry because of worker inefficiency.
Another way workers can be protected is for the building contractor to erect safety nets in order to provide protection against falls. Cost and maintenance of such safety nets, as well as the equipment and expense required for erecting and dismantling the net and associated equipment, and moving and storing the net and equipment, can be a substantial increment in the per square foot cost of especially the roof insulation system being installed.
With the anticipation of expanded enforcement efforts by government safety officials, building erectors have increasing incentive to find ways to meet the existing fall protection requirements.
Another acceptable type of fall protection system is a passive system wherein a fabric, such as a solid sheet, a woven sheet, or a net-like material, is suspended at or below the work area, optionally supported by a grid of crossing support bands, far enough above any underlying supporting surface to catch and support a worker who falls, thereby to act as a passive fall-protection system.
OSHA has defined a drop test procedure whereby a such passive fall protection system can be tested. According to the test procedure, a 400 pound weight is dropped onto the fall protection system under stated conditions to determine whether a given system meets the required safety standards. For purposes of complying with government regulations, any system used as a fall protection system need only meet the OSHA-mandated standards related to dropping such 400 pound weight. Of course, the real humanitarian objective is to prevent worker injuries if/when a worker falls from an elevated work location. Thus, any fall protection system which is effective to catch and safely hold a falling worker has operational value, even if such system does not meet OSHA standards.
According to one aspect of the prior art, currently in use in the metal building industry, and intended to meet OSHA fall protection standards, a purported fall protection system uses crossing longitudinal and lateral metal bands extending under the eave, under the ridge, and under the intermediate purlins. A suspension fabric is installed above the bands and under the purlins, the eaves, and the ridges, extending across the entirety of the width of a respective bay of the building being constructed, thereby providing a suspended fabric intended to catch and support a falling worker in that bay. Insulation is ultimately installed on top of the fabric whereby the fabric ultimately functions as the vapor barrier portion of the building ceiling insulation system in the finished building.
Suspension fabric is fabricated to specific dimensions for each given building being constructed. Thus, sheets of fabric may be seamed together longitudinally in order to make a finished fabric which can extend the full length, e.g. eave to ridge, and the full width, of a particular bay of a particular building being constructed.
Once the length and width of the fabric have been established and so fabricated, the fabric is Z-folded such that the creases in the “Z” extend along the width of the fabric, and such that the width of the so-Z-folded fabric is less than the specified width along the run, from rafter to rafter, between adjacent ones of the purlins in the building being constructed. In conventionally-known fabrication of the fabric, starting at one end of the Z-folded construction, a length of the thus-Z-folded fabric is then repeatedly folded onto itself in e.g. 3-foot long segments until the entirety of the Z-folded length has been incorporated into the folded-onto-itself construct.
The resulting bundle of fabric somewhat resembles a folded tarp. Such folded bundle of product may be about 3 feet long along the width of the sheeting and up to 3-4 feet long in a cross direction along that length of the sheet which will ultimately be installed between the eave and the ridge of the building.
The so-folded product bundle can be wrapped in e.g. plastic film. The resulting product bundle typically contains quite a bit of air such that the bundle is soft, thus somewhat dimensionally unstable. The bundle can also be weighty, typically weighing about 50 pounds to about 80 pounds.
Once at the construction site, the so-folded conventionally-fabricated suspension fabric is raised to an elevation above its installation height, and placed onto a grid-work of widely-spaced longitudinal and lateral support bands in a bay into which the fabric is to be installed, with the width of the fabric extending dimensionally along the width of the building bay, and the length of the fabric extending between the ridge and the eave of the building. The plastic packaging film is then removed and the bundle is unfolded across the width of the respective bay. With the fabric bundle thus unfolded, the fabric is still in, its Z-folded configuration, extending across essentially the full width of the bay.
Once the fabric has been extended across generally the full width of the bay, still in the Z-folded configuration, the side edges of the fabric, namely those edges which extend along the lengths of the respective first and second rafters, are in position proximate the respective ones of the rafters. Opposing ends of the fabric, which are designed to extend along the eave and the ridge, are then worked under the purlins, under the eaves and under the ridges, thus to extend the fabric the full extent of its length and width in the bay.
Such “positioning” of the fabric presents certain challenges. First, the dimensionally unstable fabric bundle is difficult to handle because of its dimensional instability. The bundle is initially placed at elevation on a collection of discontinuous surfaces, namely on top of the first rafter and/or on a longitudinal band. The fabric bundle may also overlie a lateral band and thus be supported by both a longitudinal band and a lateral band. As can be seen in FIGS. 2 and 4, the banding and the rafter present relatively small support surface areas for supporting the fabric bundle, and substantial-size openings, spacings, are disposed between such respective support members.
Thus, balancing the dimensionally-unstable fabric bundle on such small support surfaces presents a first challenge.
A second challenge is found in the unfolding of the fabric bundle across the width of the bay to the second rafter. Namely, and referring to FIGS. 2 and 4, in order for a worker to get enough leverage to be able to manipulate the fabric bundle across the band grid-work, the worker, working from an e.g. scissors and/or other hydraulic lift, will typically be high enough to stick his head up above the band grid-work in order to be able to handle the heavy fabric bundle, namely to effectively control the fabric bundle while unfolding the fabric bundle across the width of the bay. So the process of getting the fabric onto supports in the bay, and the process of extending the fabric across the bay, are strenuous, labor-intensive tasks.
The instructions known to the applicants herein, for positioning the fabric, simply say “unwrap and position . . . the fabric between . . . two purlins”. But there is no teaching in the art regarding how one efficiently, and safely, unwraps the fabric, and positions the fabric onto the band grid-work across that open space. The process of unwrapping the fabric may be straight-forward, because the fabric need not be moved in order to unwrap the fabric. However, the “positioning” of the fabric requires movement of the fabric, as well as change in the form of the fabric product, from a folded, bundle form to that of a flat, multiple-layer, Z-folded temporary form. And while the grid-work of banding can support the unfolded, laid-out-flat. Z-folded fabric, across the bay between the first and second rafters, the banding does not, will not, safely support a worker. And in the process of “positioning” the fabric, laid out flat between the purlins, the Z-folded fabric must be manipulated across the width of the bay.
Accordingly, there is a need for an easier, more efficient method of positioning the fabric at the working, install elevation.
Further, there is a need for a more efficient method of extending the fabric across the width of the bay in the process of installing the fabric over the bay.
Further, there is a need to provide a novel fabric product which is more easily extended/distributed across the width of the bay.
Yet further, there is a need to provide a novel method of converting the suspension fabric material into a fabric product which is easier to position and install.
These and other needs are alleviated, or at least attenuated, or partially or completely satisfied, by novel products, systems, and/or methods of the invention.